bindep 2.0.0

Introduction

Bindep is a tool for checking the presence of binary packages needed to use an application / library. It started life as a way to make it easier to set up a development environment for OpenStack projects. While OpenStack depends heavily on pip for installation of Python dependencies, some dependencies are not Python based, and particularly for testing, some dependencies have to be installed before pip can be used - such as virtualenv and pip itself.

Basics

Create a file called other-requirements.txt and in that list any requirements your application / library has. In your README or INSTALL or other documentation you can tell users to run bindep to report on missing dependencies. Users without bindep installed can consult the other-requirements.txt file by hand if they choose, or install bindep first and then use it.

The output from bindep is fairly verbose normally, but passing an option of -b/–brief outputs just the missing packages one per line, suitable for feeding to your package management tool of choice.

If you need to maintain multiple requirements list files you can pass a specific filename with the -f/–file command line option. If you want to read the list from standard input in a pipeline instead, use a filename of “-“.

When bindep runs, its exit code is 0 if no described packages are missing, but 1 if there are packages which it believes need to be installed.

$ bindep test

$ bindep --profiles

Writing Requirements Files

The requirements file other-requirements.txt lists the dependencies for projects. Where non-ascii characters are needed, they should be UTF8 encoded.

The file is line orientated - each line is a Debian binary package name, an optional profile selector and optional version constraints. (Note - if you are writing an alternative parser, see the Debian policy manual for the parsing rules for packagenames). Debian package names are used as a single source of truth - bindep can be taught the mapping onto specific packaging systems. Alternatively, profiles may be used to encode platform specific requirements.

Profiles are used to decide which lines in the requirements file should be considered when checking dependencies. Profile selectors are a list of space separated strings contained in []. A selector prefixed with ! is a negative selector. For a line in the requirements file to be active:

• it must not have a negative selector that matches the active profile.

• it must either have no positive selectors, or a positive selector that matches the active profile.

For instance, the profile selector [!qpid] will match every profile except qpid and would be suitable for disabling installation of rabbitmq when qpid is in use. [default] would match only if the user has not selected a profile (or selected default). [default postgresql test] would match those three profiles but not mysql. [platform:rhel] will match only when running in a RHEL linux environment.

Note that platform selectors are treated as kind of filter: If a line contains a platform selector, then the package only gets installed if at least one of the platform selectors matches in addition to the match on the other selectors. As an example, [platform:rpm test] would only install a package on a RPM platform if the test selector is used.

Version constraints are a comma separated list of constraints where each constraint is (== | < | <= | >= | > | !=) VERSION, and the constraints are ANDed together (the same as pip requirements version constraints).

Comments are allowed: everything from the first # to the end of the line is ignored.

Developing bindep

Either install bindep and run bindep test to check you have the needed tools, or review other-requirements.txt by hand.

pip install -r requirements.txt -r test-requirements.txt